Prepare to publish for stable null safety (#103)

Add CI testing on the oldest supported stable SDK.

pkgs/oauth2/.github/workflows/test-package.yml

@@ -13,14 +13,14 @@ env:
   PUB_ENVIRONMENT: bot.github
 
 jobs:
-  # Check code formatting and static analysis on a single OS (linux)
-  # against Dart dev.
+  # Check code formatting and lints against Dart dev, check analyzer warnings
+  # against the oldest supported SDK.
   analyze:
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        sdk: [dev]
+        sdk: [2.12.0, dev]
     steps:
       - uses: actions/checkout@v2
       - uses: dart-lang/[email protected]
@@ -31,10 +31,13 @@ jobs:
         run: dart pub get
       - name: Check formatting
         run: dart format --output=none --set-exit-if-changed .
-        if: always() && steps.install.outcome == 'success'
+        if: matrix.sdk == 'dev' && steps.install.outcome == 'success'
       - name: Analyze code
         run: dart analyze --fatal-infos
-        if: always() && steps.install.outcome == 'success'
+        if: matrix.sdk == 'dev' && steps.install.outcome == 'success'
+      - name: Analyze code
+        run: dart analyze
+        if: matrix.sdk != 'dev' && steps.install.outcome == 'success'
 
   # Run tests on a matrix consisting of two dimensions:
   # 1. OS: ubuntu-latest, (macos-latest, windows-latest)
@@ -47,7 +50,7 @@ jobs:
       matrix:
         # Add macos-latest and/or windows-latest if relevant for this package.
         os: [ubuntu-latest]
-        sdk: [dev]
+        sdk: [2.12.0, dev]
     steps:
       - uses: actions/checkout@v2
       - uses: dart-lang/[email protected]

pkgs/oauth2/CHANGELOG.md

@@ -1,4 +1,4 @@
-# 2.0.0-dev
+# 2.0.0
 
 * Migrate to null safety.
 

pkgs/oauth2/pubspec.yaml

@@ -1,13 +1,13 @@
 name: oauth2
-version: 2.0.0-dev
+version: 2.0.0
 homepage: https://github.com/dart-lang/oauth2
 description: >-
   A client library for authenticating with a remote service via OAuth2 on
   behalf of a user, and making authorized HTTP requests with the user's
   OAuth2 credentials.
 
 environment:
-  sdk: '>=2.12.0-0 <3.0.0'
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   collection: ^1.15.0